BMI Calculator for Teens
Estimate a teen BMI and understand why growing adolescents need BMI-for-age interpretation rather than adult cutoffs.
BMI Calculator for Teens
Medical Disclaimer: Teen BMI bands are approximate. For clinical decisions, use CDC BMI-for-age percentiles with a clinician.
How this is calculated
Formula: BMI = weight ÷ height², interpreted approximately by age and sex
The basic BMI equation is the same at every age: kilograms divided by meters squared.
For ages 2–19, clinicians interpret that value on sex- and age-specific growth charts. Percentiles compare a teen with peers of the same age and sex; adult BMI categories are not appropriate.
This tool can only provide an approximate BMI-for-age context. Exact assessment depends on date of birth, measurement quality, growth pattern, puberty, medical history, and the growth chart used.
Common BMI-for-age percentile labels
| Screening label | Percentile | Important note |
|---|---|---|
| Underweight | Below 5th | Needs professional growth review |
| Healthy-weight range | 5th to below 85th | One part of overall health |
| Overweight | 85th to below 95th | Confirm growth trend and context |
| Obesity | 95th or above | Use supportive, clinician-led assessment |
Support healthy growth
Tips
- •Review results with a parent, guardian, school nurse, pediatrician, or family doctor.
- •Focus on regular meals, sleep, movement, and wellbeing—not restrictive dieting.
- •Use repeated clinical growth measurements rather than one home result.
- •Avoid comparing bodies with friends or social-media images.
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Frequently asked questions
There is no single healthy teen BMI number. Clinicians use age- and sex-specific percentiles, growth history, puberty, and overall health.
This educational estimate is not medical advice and must not be used to prescribe weight loss, calorie restriction, or an “ideal” weight for a teen.
Teen BMI requires age- and sex-specific growth-chart interpretation and this calculator is only approximate. A teen should review any concern with a parent or guardian and a pediatric clinician, who can assess growth history, puberty, nutrition, and wellbeing. Do not start a diet based on this result.
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